Combining ASP.NET WebForms and ASP.NET MVC

I created a page route to integrate my MVC application with a WebForms page that exist in my project:

public static void RegisterRoutes(RouteCollection routes)
{    
routes.IgnoreRoute("{resource}.axd/{*pathInfo}");    
// register the report route    
routes.MapPageRoute("Reports","Reports","~/Pages/ReportViewer.aspx");    
routes.MapRoute("Default","{controller}/{action}/{id}", new { controller = "Home", action = "Index", id = UrlParameter.Optional });
}

This works when browsing to the specific url’s. However, I noticed this route created a problem whenever I use an  Html.ActionLink in my Views:




<%: Html.ActionLink("Home", "Index", "Home") %>

When I load the page in the browser the link appears like:

http://localhost:12345/reports/test?action=Index&controller=Home

Unfortunately I can't place the route at the bottom, since the webform route has more specific parameters than the MVC route. I was able to solve this problem by introducing a new constraint.

I created a new constraint called IncomingRequestConstraint. This constraint  simply return false for outgoing Urls(so that all Html helpers will work as expected).

public class IncomingRequestConstraint : IRouteConstraint
{
public bool Match(HttpContextBase httpContext, Route route, string parameterName, RouteValueDictionary values, RouteDirection routeDirection)
{
return routeDirection==RouteDirection.IncomingRequest;
}
}

In the global.asax, I added this constraint to the WebForms route:

routes.IgnoreRoute("{resource}.axd/{*pathInfo}");    
// register the report routes    
routes.MapPageRoute("Reports","Reports","~/Pages/ReportViewer.aspx", false, null, new RouteValueDictionary(new { controller = new IncomingRequestConstraint() }));